My guess is, we could discuss the possibilities of the saber physics if we could stick to the basic rule of science fiction cogitation: "IF it existed, how could it be explained?"
Well, my thought is, if everyone believes shields are possible, so are lightsabers, cause, if shields deflect light, you can also contain the light and make alightsaber

"There is only one truth in our universe: The light and the dark side are one, and are equal: this is the balance of the Force!"